Massive galaxy survey confirms accelerating Universe

The Universe is definitely getting bigger, faster—and astronomers using the Anglo-Australian Telescope in NSW have confirmed it.

The WiggleZ survey looked at over 200,000 visible galaxies (centre), but also gave insights into dark matter (the green grid that deforms the gravity field) and dark energy (the purple grid). Credit: NASA/JPL-Caltec

The results are now in for WiggleZ, a survey of the night sky, spanning 200,000 galaxies and billions of years of cosmic history.

“This puts a nail in it. Clearly the universe is accelerating, and clearly there is something like dark energy,” says Prof Matthew Colless, director of the Australian Astronomical Observatory and a member of the WiggleZ team.By detecting the patterns in the way galaxies are distributed in time and space, WiggleZ was able to confirm claims that there must be an unseen force in addition to gravity.

Without this force, which physicists call dark energy, the distribution of galaxies in the universe would be quite different.

This independently verifies the discovery of the accelerating expansion of the Universe that won Australian astronomer Prof Brian Schmidt the 2011 Nobel Prize.

“We found exactly what we set out to look for. That’s a bit boring in one way, but really it’s a beautiful confirmation of our best theory so far for how the Universe is put together,” says Matthew.

In 2012, astronomers announced that the Square Kilometre Array radio telescope will be shared between southern Africa and Australia-New Zealand. One of the tasks of the Australian component, building on the Australian Square Kilometre Array Pathfinder (ASKAP), will be to conduct another galactic survey.

This new survey, called WALLABY, will look for the signature of dark energy in both the distribution of galaxies and their motions by surveying half a million galaxies across three-quarters of the sky. This new survey, called WALLABY, will look for the signature of dark energy in both the distribution of galaxies and their motions by surveying half a million galaxies across three-quarters of the sky.

Photo: The WiggleZ survey looked at over 200,000 visible galaxies (centre), but also gave insights into dark matter (the green grid that deforms the gravity field) and dark energy (the purple grid).